Display Port to HDMI connected monitor not being detected

I have an HP EliteBook 840 G3 laptop with Windows 10 on it which is plugged into the DisplayLink Plug and Display dock. I have 2 - 22" LCD displays plugged into the dock. One with a DVI to DVI cable and the other with a Display Port to HDMI cable. I've downloaded and installed you latest drivers. I've rebooted both the laptop and the dock. The DVI to DVI monitor is working fine, the Display Port to HDMI display is not (it is black like not connected). When I look at Windows Display Properties, it is only showing the one monitor. How do I fix this?

Alan also reached out to us directly via support@plugable.com for help and I have already sent my direct reply, but for the benefit of anyone else following this thread the relevant portions of my direct reply are:

Based on your description, the cause of the behavior is the cable you are using that has an HDMI connector on one end and a DisplayPort connector on the other. This is a passive cable that is only meant to work in one direction and is intended to convert a DisplayPort ++ output to a HDMI input, and not the other way around as you are trying to do. I actually wrote about the cable options for our dock here if you are curious -> http://plugable.com/2015/07/06/video-...

A possible solution if both of the monitors you are connecting to the dock have DVI inputs, you could purchase separately an inexpensive HDMI to DVI cable like this -> http://amazon.com/dp/B014I8UQJY to connect the second display. In other words, things would be connected like so: